WEBVTT 0 00:00:00.320 --> 00:00:02.120 Andrew Dunkley: Hello again and thank you for joining us. 1 00:00:02.120 --> 00:00:04.680 This is a Q and A edition of Space Nuts. This 2 00:00:04.680 --> 00:00:07.480 is where we stand in a queue and go, 3 00:00:07.480 --> 00:00:10.410 ah. Or not. Um, 4 00:00:11.040 --> 00:00:12.920 no, it's where we answer audience questions. 5 00:00:12.920 --> 00:00:15.080 We've got questions today about weight 6 00:00:15.080 --> 00:00:17.600 variations on Earth, depending on where you 7 00:00:17.600 --> 00:00:20.320 are. Um, I know we've been down that road 8 00:00:20.320 --> 00:00:22.560 before, but, um, we're going to do it again. 9 00:00:22.960 --> 00:00:25.480 Uh, the age of the solar system has been 10 00:00:25.480 --> 00:00:28.000 brought up again. Visiting, uh, another star. 11 00:00:28.640 --> 00:00:30.960 Would we be able to do that anytime soon? 12 00:00:32.060 --> 00:00:34.500 And Earth, uh, minus the moon. A what if 13 00:00:34.500 --> 00:00:37.420 question that we have done a trillion times. 14 00:00:37.420 --> 00:00:39.500 But, um, why not? Let's 15 00:00:39.900 --> 00:00:42.620 reroute to that little, um, what if 16 00:00:42.620 --> 00:00:44.180 scenario. That's all coming up on this 17 00:00:44.180 --> 00:00:46.060 edition of space nuts. 18 00:00:46.140 --> 00:00:48.620 Professor Fred Watson: 15 seconds. Guidance is internal. 19 00:00:48.860 --> 00:00:51.500 10, 9. Ignition 20 00:00:51.500 --> 00:00:52.540 sequence start. 21 00:00:52.700 --> 00:00:53.421 Professor Fred Watson: Space nuts. 22 00:00:53.493 --> 00:00:56.280 Professor Fred Watson: 5, 4, 3, 2. 1, 2, 3, 4, 23 00:00:56.351 --> 00:00:58.460 5, 5, 4, 3, 2, 1. 24 00:00:58.540 --> 00:00:59.740 Andrew Dunkley: Space nuts. 25 00:00:59.740 --> 00:01:01.580 Professor Fred Watson: Astronauts report it feels good. 26 00:01:02.560 --> 00:01:04.800 Andrew Dunkley: And he's back again to solve all your 27 00:01:04.800 --> 00:01:06.440 riddles. It's Professor Fred Watson Watson, 28 00:01:06.440 --> 00:01:07.960 astronomer at large. Hello, Fred Watson. 29 00:01:07.960 --> 00:01:10.720 Professor Fred Watson: Hello, Andrew. I'm glad to be a 30 00:01:10.720 --> 00:01:11.520 riddle solver. 31 00:01:11.760 --> 00:01:14.680 Andrew Dunkley: Yes, it's a good thing to do, even when you 32 00:01:14.680 --> 00:01:16.760 can't. You can just pretend. That's what we 33 00:01:16.760 --> 00:01:19.720 do all the time. I like the Q and 34 00:01:19.720 --> 00:01:21.920 A edition. It gives us a chance to hear other 35 00:01:21.920 --> 00:01:24.120 voices from around the world who listen to 36 00:01:24.120 --> 00:01:26.800 us. And, um, sometimes we learn more about 37 00:01:26.800 --> 00:01:29.800 them than we expect to. Like, um, Andy the 38 00:01:29.800 --> 00:01:32.760 train driver in Sydney. And, uh, we've had 39 00:01:32.760 --> 00:01:35.380 a few over the years. Rusty from Donnybrook, 40 00:01:35.380 --> 00:01:37.900 one of our regular sender innerers. And, 41 00:01:38.240 --> 00:01:40.220 um, Sandy in Melbourne and, 42 00:01:40.860 --> 00:01:43.860 oh, gosh, um, and plenty 43 00:01:43.860 --> 00:01:46.300 of others. Plenty, uh, of others. And if I 44 00:01:46.300 --> 00:01:47.580 didn't name you, and I should have, I 45 00:01:47.580 --> 00:01:50.460 apologise. Martin. We should not, not mention 46 00:01:50.460 --> 00:01:51.020 Martin. 47 00:01:51.580 --> 00:01:53.020 Professor Fred Watson: We've got pilots as well. 48 00:01:53.180 --> 00:01:54.980 Andrew Dunkley: We have. We have Hannah. 49 00:01:54.980 --> 00:01:55.580 Professor Fred Watson: That's right. 50 00:01:55.580 --> 00:01:57.300 Andrew Dunkley: Haven't heard from her in ages, but I hope 51 00:01:57.300 --> 00:02:00.220 she's well. Now, um, let's, 52 00:02:00.320 --> 00:02:01.820 uh, maybe get to our first question. 53 00:02:01.820 --> 00:02:02.260 Fred Watson. 54 00:02:02.260 --> 00:02:04.140 This comes from dj. 55 00:02:05.680 --> 00:02:07.920 DJ: Hi, guys. DJ from 56 00:02:07.920 --> 00:02:10.480 Indianapolis, Indiana, usa. 57 00:02:12.000 --> 00:02:14.920 You, in a recent podcast, 58 00:02:14.920 --> 00:02:16.720 talked about how if 59 00:02:17.680 --> 00:02:20.640 a person weighed a hundred kilogrammes 60 00:02:20.640 --> 00:02:23.280 on the North Pole, that they would weigh 61 00:02:23.920 --> 00:02:26.880 99 at the equator. My question would 62 00:02:26.880 --> 00:02:29.480 be, if you were to take a submarine up to the 63 00:02:29.480 --> 00:02:31.990 North Pole, you pop up through the ice, you 64 00:02:31.990 --> 00:02:33.710 hop out with your bathroom scale, 65 00:02:35.390 --> 00:02:38.270 stand on the ice and it says you 66 00:02:38.430 --> 00:02:41.230 weigh 100 kilogrammes. You take that 67 00:02:41.230 --> 00:02:44.070 same scale, drive the sub down 68 00:02:44.070 --> 00:02:46.950 to, say, Ecuador, get out on the 69 00:02:46.950 --> 00:02:49.630 beach, put your bathroom scale down and now 70 00:02:49.790 --> 00:02:52.190 would it then say you weighed 99. 71 00:02:52.910 --> 00:02:55.310 Or are bathroom scales 72 00:02:55.310 --> 00:02:57.960 calibrated for, 73 00:02:58.760 --> 00:03:01.480 uh, Earth's gravity at, 74 00:03:01.560 --> 00:03:03.640 say, the equator? And it would say you 75 00:03:03.640 --> 00:03:06.280 weighed 99 at the north 76 00:03:06.280 --> 00:03:08.600 Pole too. Would you need 77 00:03:08.840 --> 00:03:11.040 scientific instruments to tell the 78 00:03:11.040 --> 00:03:12.760 difference? Or could a normal person with a 79 00:03:12.760 --> 00:03:15.640 normal scale tell that they 80 00:03:15.640 --> 00:03:18.480 weighed a kilogramme less at the pole than 81 00:03:18.480 --> 00:03:21.240 they do at the equator? Thanks, guys. 82 00:03:22.280 --> 00:03:24.200 Andrew Dunkley: All right, the first floor in. His question 83 00:03:24.200 --> 00:03:26.520 is, putting the scales on sand 84 00:03:27.090 --> 00:03:30.010 would probably completely mess him up. But 85 00:03:30.010 --> 00:03:32.680 look, we know we get the gist. Um, 86 00:03:32.930 --> 00:03:35.810 yeah. 100 kilogrammes on the North Pole. Same 87 00:03:35.810 --> 00:03:38.410 set of scales at the equator. Or 88 00:03:38.410 --> 00:03:41.370 Ecuador, 99 kilos. Does that sound about 89 00:03:41.370 --> 00:03:41.730 right? 90 00:03:41.890 --> 00:03:44.760 Professor Fred Watson: It is. It's perfectly right, yeah. Uh, 91 00:03:44.760 --> 00:03:47.090 and it would show up on the scale. I mean, 92 00:03:48.850 --> 00:03:51.730 bathroom scales are notoriously inaccurate. 93 00:03:52.690 --> 00:03:54.610 They're not accurate to 1%. 94 00:03:55.520 --> 00:03:58.100 Um, but, but if you did have a really 95 00:03:58.100 --> 00:04:01.020 accurate scale and you can get them, um, 96 00:04:01.060 --> 00:04:03.660 then it would show the difference. Uh, it 97 00:04:03.660 --> 00:04:06.580 would be 100 kilogrammes, uh, on the pole, 98 00:04:06.580 --> 00:04:08.660 99 at, uh, the equator. 99 00:04:09.270 --> 00:04:12.220 Um, and that's because what 100 00:04:12.220 --> 00:04:15.220 you're measuring your weight against is 101 00:04:15.220 --> 00:04:17.460 something that doesn't change with 102 00:04:17.940 --> 00:04:20.780 gravity, and that's the spring. Um, you know, 103 00:04:20.780 --> 00:04:22.100 you're standing on something that's spring 104 00:04:22.100 --> 00:04:24.860 loaded and the spring behaves the same. No 105 00:04:24.860 --> 00:04:26.740 matter what gravitational field you're in, it 106 00:04:26.900 --> 00:04:29.480 still exerts the same force force. And so it 107 00:04:29.480 --> 00:04:32.280 will feel less weight from you at the 108 00:04:32.280 --> 00:04:34.880 equator, uh, uh, than it does at, uh, the 109 00:04:34.880 --> 00:04:36.560 poles. Now, 110 00:04:37.570 --> 00:04:40.400 um, I think that's fairly common knowledge 111 00:04:40.560 --> 00:04:43.200 that that happens, that you weigh less. 112 00:04:43.440 --> 00:04:45.680 Probably most people don't realise that it is 113 00:04:45.680 --> 00:04:48.480 actually 1%. It's almost exactly 1%, which is 114 00:04:48.480 --> 00:04:50.960 a bit of a coincidence, uh, but it has 115 00:04:51.520 --> 00:04:54.400 four sources, uh, not just one. 116 00:04:54.960 --> 00:04:57.870 So the weight that 117 00:04:57.870 --> 00:05:00.530 you feel are determined, uh, 118 00:05:01.270 --> 00:05:03.790 by first of all, the Earth's gravity, 119 00:05:04.190 --> 00:05:06.510 which is a property of the planet. 120 00:05:06.990 --> 00:05:09.590 But then you've got the moon's, the sun's 121 00:05:09.590 --> 00:05:12.230 gravity as well, pulling on you and the 122 00:05:12.230 --> 00:05:15.110 moon's gravity too. And 123 00:05:15.110 --> 00:05:16.870 then the thing that I think most people think 124 00:05:16.870 --> 00:05:19.790 about is the centrifugal force, the fact that 125 00:05:19.790 --> 00:05:22.420 the Earth is rotating and that gravity gives 126 00:05:22.420 --> 00:05:24.380 you a centrifugal force that tends to lift 127 00:05:24.380 --> 00:05:25.220 you a little bit. 128 00:05:26.070 --> 00:05:26.210 Professor Fred Watson: Um, 129 00:05:28.420 --> 00:05:30.780 Professor Fred Watson: and that's the case when you look at the 130 00:05:30.780 --> 00:05:32.620 sun's gravity and the moon's gravity. They're 131 00:05:32.620 --> 00:05:35.460 basically very, very 132 00:05:35.460 --> 00:05:38.339 small, uh, and they tend to cancel out. 133 00:05:38.339 --> 00:05:40.980 Anyway, uh, the 134 00:05:40.980 --> 00:05:43.820 centrifugal force comes about 135 00:05:43.820 --> 00:05:46.820 because on the equator, you're travelling at 136 00:05:46.820 --> 00:05:49.700 1600 kilometres an hour, uh, eastwards, 137 00:05:50.020 --> 00:05:52.500 and that Motion, because it's in a 138 00:05:52.850 --> 00:05:55.170 curve, uh, has an acceleration 139 00:05:55.650 --> 00:05:58.370 represented which cancels out a little bit of 140 00:05:58.370 --> 00:06:01.170 the gravity. Uh, but the other one is 141 00:06:01.250 --> 00:06:03.490 the Earth's gravity itself is different. 142 00:06:04.370 --> 00:06:06.930 Even if the Earth was not rotating, there 143 00:06:06.930 --> 00:06:08.970 would still be a difference at uh, the 144 00:06:08.970 --> 00:06:11.690 equator, uh, uh, from the pole. And that's 145 00:06:11.690 --> 00:06:13.290 because the Earth, uh, is not a perfect 146 00:06:13.290 --> 00:06:15.730 sphere. It's what we call an oblate spheroid. 147 00:06:15.890 --> 00:06:18.650 It's slightly flattened. So you're, I can't 148 00:06:18.650 --> 00:06:21.050 remember how far it is, you're 30 kilometres 149 00:06:21.050 --> 00:06:23.930 away or something like that, further away at 150 00:06:23.930 --> 00:06:25.830 the equator, greater from the centre of the 151 00:06:25.830 --> 00:06:27.740 Earth, uh, uh, than you are, 152 00:06:27.740 --> 00:06:30.430 uh, the pole. Let me just, I can 153 00:06:30.590 --> 00:06:33.470 do this in my head. Uh, it's actually 154 00:06:34.110 --> 00:06:36.750 21 kilometres is the difference. 155 00:06:37.230 --> 00:06:40.190 You're 21 kilometres further from 156 00:06:40.349 --> 00:06:43.030 the centre of the Earth when you're on the 157 00:06:43.030 --> 00:06:45.950 equator than you are at the pole. And that 158 00:06:45.950 --> 00:06:48.070 means you're higher up until you feel 159 00:06:48.070 --> 00:06:50.510 slightly less gravity. And when you add that 160 00:06:50.510 --> 00:06:52.960 to the gravity change you get because of the 161 00:06:52.960 --> 00:06:55.480 Earth's rotation, it comes to basically 1%. 162 00:06:56.400 --> 00:06:59.320 Uh, so. Really? Yeah, quite, quite, um, um, 163 00:06:59.400 --> 00:07:01.960 a nice calculation and also 164 00:07:02.120 --> 00:07:04.360 quite a nice question from Vijay because 165 00:07:04.660 --> 00:07:07.400 uh, or DJ I didn't quite catch which. 166 00:07:07.760 --> 00:07:10.720 Uh, but good to hear from you in Indiana. Uh, 167 00:07:10.720 --> 00:07:13.320 and it's a well directed question, uh, but 168 00:07:13.320 --> 00:07:15.320 the answer is yes, you'd see on your bathroom 169 00:07:15.320 --> 00:07:16.760 scale if it was accurate enough. 170 00:07:16.760 --> 00:07:19.760 Andrew Dunkley: Yes, uh, we took some bathroom 171 00:07:19.760 --> 00:07:22.590 scales on a cruise ship once and um, yeah, 172 00:07:22.590 --> 00:07:24.950 don't use them at sea. I weighed everything 173 00:07:24.950 --> 00:07:27.270 from 60 to 190 kilos 174 00:07:27.990 --> 00:07:29.270 in a matter of seconds. 175 00:07:32.420 --> 00:07:34.870 Uh, it does remind me though of when I was a 176 00:07:34.870 --> 00:07:37.670 kid. My dad was a pharmacist for his, almost 177 00:07:37.670 --> 00:07:40.470 his entire career. And back then when 178 00:07:40.470 --> 00:07:43.430 you didn't have scales at home or you know, 179 00:07:43.430 --> 00:07:45.710 very few people did, you'd go down to the 180 00:07:45.710 --> 00:07:48.520 chemist, uh, and you'd put, uh, 181 00:07:48.630 --> 00:07:51.590 in Australia you'd put 20 cents in the slot 182 00:07:51.590 --> 00:07:53.390 and stand on the scales and it would give you 183 00:07:53.390 --> 00:07:55.930 an accurate weight. Wait, last time I used 184 00:07:55.930 --> 00:07:57.730 one of those I was 11 stone. 185 00:08:00.450 --> 00:08:01.650 Professor Fred Watson: Yes, things are moving. 186 00:08:01.650 --> 00:08:04.370 Andrew Dunkley: I still remember 11 stone. Now 11 stone, 187 00:08:05.000 --> 00:08:06.690 um, doesn't mean much anymore. 188 00:08:07.400 --> 00:08:09.730 Um, but I'll work it out. 189 00:08:10.290 --> 00:08:12.290 Equals kilos 190 00:08:13.570 --> 00:08:16.530 and the answer is 69.85 kilos. 191 00:08:16.530 --> 00:08:18.690 Well, I weigh a little bit more than that 192 00:08:18.690 --> 00:08:19.010 now. 193 00:08:19.250 --> 00:08:20.610 Professor Fred Watson: Probably not that much more. 194 00:08:21.060 --> 00:08:24.060 Andrew Dunkley: Um, about 15 kilos more. 195 00:08:26.780 --> 00:08:27.140 Professor Fred Watson: Yeah. 196 00:08:27.140 --> 00:08:29.940 Andrew Dunkley: 11 stone back in the day. Yes, I was quite 197 00:08:29.940 --> 00:08:32.900 proud of that. But uh, you don't see them 198 00:08:32.900 --> 00:08:35.180 anymore, do you, those uh, scales out in 199 00:08:35.180 --> 00:08:36.060 front of the pharmacies. 200 00:08:36.620 --> 00:08:39.420 Professor Fred Watson: They used to be. You found them on railway 201 00:08:39.420 --> 00:08:41.340 stations as well in Britain? I don't know 202 00:08:41.340 --> 00:08:41.540 why. 203 00:08:41.540 --> 00:08:43.180 Andrew Dunkley: Yeah, well, they used to have them at 204 00:08:43.180 --> 00:08:45.540 railway, uh, stations for weighing packages 205 00:08:45.540 --> 00:08:48.540 and things like that and post offices and 206 00:08:48.540 --> 00:08:51.350 things. Yeah, yeah, yeah. 207 00:08:51.350 --> 00:08:53.190 All right, dj, thanks for the question, but, 208 00:08:53.190 --> 00:08:54.950 yeah, it's true. If you were to take a 209 00:08:54.950 --> 00:08:56.950 submarine, pop up at the North Pole, put your 210 00:08:56.950 --> 00:08:59.350 scales down and weigh 100, then go to 211 00:08:59.350 --> 00:09:02.350 Ecuador and do the same thing, you'd weigh 212 00:09:02.350 --> 00:09:02.910 99. 213 00:09:04.220 --> 00:09:06.800 Um, now our next question, Fred Watson. Uh, 214 00:09:06.800 --> 00:09:09.670 it comes from Nick, uh, who is in 215 00:09:09.670 --> 00:09:12.310 Cambridge in the uk. He said Cambridge, the 216 00:09:12.310 --> 00:09:14.510 UK one, just so we didn't get confused with 217 00:09:14.510 --> 00:09:16.870 Cambridge in the United States. I assume 218 00:09:16.870 --> 00:09:19.830 there'd probably be more than two. Um, now 219 00:09:19.830 --> 00:09:22.010 he says, as you answered my previous question 220 00:09:22.010 --> 00:09:24.450 so eloquently, I came back for a second 221 00:09:24.450 --> 00:09:26.730 helping. We must have been rude. Wouldn't 222 00:09:26.730 --> 00:09:29.290 have been you, Fred Watson. Uh, the solar 223 00:09:29.290 --> 00:09:32.130 system is, uh, 4.6 ish billion 224 00:09:32.130 --> 00:09:34.700 years old, but it formed from, uh, 225 00:09:34.700 --> 00:09:37.530 material that is older. Are there any 226 00:09:37.530 --> 00:09:40.170 estimates for how much older this 227 00:09:40.170 --> 00:09:43.050 material is? And can this help us date any 228 00:09:43.130 --> 00:09:45.770 supernovae that may have generated 229 00:09:45.770 --> 00:09:48.690 it? Uh, or was the solar system formation 230 00:09:48.690 --> 00:09:51.250 process so energetic that it reset isotope 231 00:09:51.250 --> 00:09:53.630 ratios, uh, everywhere within the sun's 232 00:09:53.630 --> 00:09:56.550 sphere of influence, much like heating rocks 233 00:09:56.630 --> 00:09:59.350 above their Curie point, uh, 234 00:09:59.350 --> 00:10:02.190 resets isotropic ratios. Thank you for the 235 00:10:02.190 --> 00:10:05.030 enlightening enlightenment twice a 236 00:10:05.030 --> 00:10:07.790 week. Uh, it keeps me relatively sane, if you 237 00:10:07.790 --> 00:10:10.390 can believe it. Nick from Cambridge, the uk, 238 00:10:10.390 --> 00:10:13.350 one, uh, I like. It's a 239 00:10:13.350 --> 00:10:15.550 good question. A couple of questions in 240 00:10:15.550 --> 00:10:18.510 there. So, yeah, um, I 241 00:10:18.510 --> 00:10:19.750 like where he's going with this. 242 00:10:19.830 --> 00:10:22.750 Professor Fred Watson: And it's one. I, um, think it's fair to say 243 00:10:22.750 --> 00:10:25.020 that this is a question still on the front 244 00:10:25.250 --> 00:10:28.210 line of research, um, because 245 00:10:30.290 --> 00:10:32.330 when you look through the, you know, the 246 00:10:32.330 --> 00:10:34.530 astronomical literature, you find a lot of 247 00:10:34.530 --> 00:10:37.330 stuff about the 248 00:10:37.650 --> 00:10:39.890 solar nebula. The solar nebula is a cloud of 249 00:10:39.890 --> 00:10:42.570 gas and dust which, um, 250 00:10:42.570 --> 00:10:45.410 basically the solar system was born in, 251 00:10:45.820 --> 00:10:47.450 uh, by this process of gravitational 252 00:10:47.450 --> 00:10:50.450 collapse. It collapses under 253 00:10:50.450 --> 00:10:53.370 its own mass, um, and starts spinning and 254 00:10:53.370 --> 00:10:55.750 you, the spinning produces a disc. So you've 255 00:10:55.750 --> 00:10:58.110 got a hot ball of gas in the middle, which 256 00:10:58.110 --> 00:11:01.110 becomes the sun, and this disc of rocky 257 00:11:01.270 --> 00:11:03.590 material and gaseous material as well 258 00:11:03.830 --> 00:11:05.800 swirling around it, which is the, um, 259 00:11:05.830 --> 00:11:08.630 protoplanetary disc. Um, when you look at 260 00:11:08.630 --> 00:11:10.550 papers, they nearly always 261 00:11:12.470 --> 00:11:12.520 Professor Fred Watson: commenting, um, 262 00:11:14.870 --> 00:11:17.670 Professor Fred Watson: on the contents of the solar nebula. 263 00:11:18.310 --> 00:11:21.190 Just in terms of the mix of gases. 264 00:11:21.190 --> 00:11:23.590 It's mostly hydrogen and helium with a few 265 00:11:24.070 --> 00:11:26.130 pollutants, which are, uh, what eventually 266 00:11:26.130 --> 00:11:28.290 made the rocky planets and the likes of us. 267 00:11:29.000 --> 00:11:31.890 Um, but there's not that much work done on 268 00:11:32.800 --> 00:11:35.560 uh, exactly the question that uh, 269 00:11:35.570 --> 00:11:37.970 Nick is uh, asking. You know, can you 270 00:11:37.970 --> 00:11:40.850 identify what supernovae 271 00:11:41.970 --> 00:11:44.530 were? Uh, uh, the 272 00:11:44.770 --> 00:11:47.130 remnants of their supernovae 273 00:11:47.130 --> 00:11:48.850 explosions, uh, which 274 00:11:49.890 --> 00:11:51.650 include heavy elements as well as the 275 00:11:51.650 --> 00:11:54.490 hydrogen and helium. Can you identify the 276 00:11:54.490 --> 00:11:57.130 dates of those supernovae? Now I have a 277 00:11:57.130 --> 00:11:59.870 recollection of seeing some papers that 278 00:11:59.870 --> 00:12:01.790 refer to evidence 279 00:12:03.310 --> 00:12:06.260 in uh, meteoritic rock. I think uh, 280 00:12:06.260 --> 00:12:09.070 that uh, suggests that some of the material 281 00:12:09.070 --> 00:12:11.710 of the solar system dates from about 8 282 00:12:11.710 --> 00:12:13.829 billion years ago. Remembering that the age 283 00:12:13.829 --> 00:12:16.470 of the solar system is more or less 4.6 284 00:12:16.470 --> 00:12:19.460 billion years, exactly as Nick says. Um, 285 00:12:19.460 --> 00:12:21.590 and we know it actually a bit more accurately 286 00:12:21.590 --> 00:12:23.590 than that, but that's the easy number to 287 00:12:23.590 --> 00:12:25.950 remember. 4.6, 4.7 billion years. 288 00:12:26.640 --> 00:12:29.310 Uh, so yes we do know it formed from material 289 00:12:29.310 --> 00:12:31.570 that, that's older but I think it's turning 290 00:12:31.570 --> 00:12:34.330 out to be quite difficult 291 00:12:34.410 --> 00:12:36.650 science to actually detect that. 292 00:12:36.950 --> 00:12:39.450 Um, and that may be 293 00:12:40.090 --> 00:12:42.170 because of the second part of his question. 294 00:12:42.170 --> 00:12:44.970 Although I suspect that the 295 00:12:44.970 --> 00:12:47.970 isotope ratios were probably preserved 296 00:12:47.970 --> 00:12:50.570 rather than destroyed as per the 297 00:12:50.570 --> 00:12:53.450 Curie point. Um, I'm sorry, this 298 00:12:53.450 --> 00:12:55.010 sounds like a waffly answer but I haven't 299 00:12:55.010 --> 00:12:57.690 really been able to pin down much research on 300 00:12:57.690 --> 00:13:00.640 this. There was a spacecraft that 301 00:13:01.840 --> 00:13:04.840 was launched um, back in, I 302 00:13:04.840 --> 00:13:07.360 think about 2001 that 303 00:13:07.990 --> 00:13:10.760 uh, it was called Genesis and it was a 304 00:13:10.760 --> 00:13:13.560 NASA, uh, experiment and the idea was to 305 00:13:13.560 --> 00:13:16.480 catch particles of the solar wind and bring 306 00:13:16.480 --> 00:13:19.480 them back to Earth. And the solar wind 307 00:13:19.480 --> 00:13:22.320 is basically nuclei of gas, 308 00:13:22.320 --> 00:13:25.280 they're mostly hydrogen, but you can also 309 00:13:25.440 --> 00:13:28.360 detect any sort of pollutants. And in a 310 00:13:28.360 --> 00:13:30.700 way what you're trying to do there's is 311 00:13:31.100 --> 00:13:32.380 analyse remnants 312 00:13:34.140 --> 00:13:37.140 of the cloud of gas and dust that form 313 00:13:37.140 --> 00:13:39.100 the solar system. You're trying to analyse 314 00:13:39.420 --> 00:13:41.660 traces of that gas and dust. And 315 00:13:43.100 --> 00:13:45.420 it's uh, similar to what we do with comets. 316 00:13:45.420 --> 00:13:47.540 We try and analyse comets to death because we 317 00:13:47.540 --> 00:13:49.820 know they're pristine objects, they've never 318 00:13:49.820 --> 00:13:52.580 been hot, they're just samples of 319 00:13:52.580 --> 00:13:54.860 the solar nebula frozen 320 00:13:55.660 --> 00:13:58.170 onto dust crystals. Uh, but 321 00:13:58.590 --> 00:14:01.520 um, Genesis unfortunately had ah, a problem. 322 00:14:01.790 --> 00:14:04.760 Um, the capsule that was sending 323 00:14:04.760 --> 00:14:07.460 back this material actually um, 324 00:14:07.460 --> 00:14:09.800 the one of the parachutes didn't open and so 325 00:14:09.800 --> 00:14:12.520 it crashed at I think it was 200 kilometres 326 00:14:12.520 --> 00:14:14.559 an hour. It hit the Earth and broke. 327 00:14:15.010 --> 00:14:17.840 Um, so there was some contamination but I 328 00:14:17.840 --> 00:14:20.080 think there was some research done on it but 329 00:14:20.080 --> 00:14:21.920 I don't think they got to the real nub of the 330 00:14:21.920 --> 00:14:24.890 matter. What's the, what's the solar 331 00:14:24.890 --> 00:14:27.770 nebula made of? Um, I'll Keep looking 332 00:14:27.770 --> 00:14:29.490 at this because it is a really interesting 333 00:14:29.490 --> 00:14:32.450 one. And, um, um, you know, if we come 334 00:14:32.450 --> 00:14:35.050 across any more definitive papers, we might 335 00:14:35.050 --> 00:14:37.690 be able to give Nick a shout out later on. 336 00:14:38.330 --> 00:14:40.410 Andrew Dunkley: So he's dug up a mystery, basically. 337 00:14:40.810 --> 00:14:41.850 Professor Fred Watson: Yeah. He's come up with. 338 00:14:41.930 --> 00:14:44.290 Andrew Dunkley: Come up with something we can't quite grapple 339 00:14:44.290 --> 00:14:44.530 with. 340 00:14:44.530 --> 00:14:46.330 Professor Fred Watson: That's right. Although I think, as I said, 341 00:14:46.330 --> 00:14:47.890 you know, and unfortunately I've been able to 342 00:14:47.890 --> 00:14:50.450 find the papers that I've read where it does 343 00:14:50.450 --> 00:14:52.250 suggest that we've got evidence for 344 00:14:52.990 --> 00:14:55.550 supernovae in the past, which are, uh, maybe 345 00:14:55.950 --> 00:14:58.630 8 billion years ago, so nearly twice the age 346 00:14:58.630 --> 00:15:01.230 of the solar system. But supernovae in the 347 00:15:01.310 --> 00:15:04.150 environment that we are now in, um, which 348 00:15:04.150 --> 00:15:06.150 would have contributed to the makeup of the 349 00:15:06.150 --> 00:15:08.510 solar system? Good question. 350 00:15:08.830 --> 00:15:11.510 Andrew Dunkley: It is fascinating. Thank you, Nick. We'll get 351 00:15:11.510 --> 00:15:14.230 back to you shortly. This is Space Nuts with 352 00:15:14.230 --> 00:15:16.670 Andrew Dunkley and Professor Fred Watson 353 00:15:16.670 --> 00:15:17.310 Watson. 354 00:15:19.540 --> 00:15:20.580 Professor Fred Watson: Step off the land now. 355 00:15:22.820 --> 00:15:25.220 That's one small step for man, 356 00:15:28.180 --> 00:15:30.980 one triumph leap for mankind. 357 00:15:31.140 --> 00:15:32.180 Andrew Dunkley: Space Nuts. 358 00:15:32.580 --> 00:15:32.980 Professor Fred Watson: Yes. 359 00:15:32.980 --> 00:15:35.940 Andrew Dunkley: And you're listening to a Q A edition. 360 00:15:35.940 --> 00:15:38.740 And our, uh, next question comes from 361 00:15:38.820 --> 00:15:39.300 Keith. 362 00:15:39.460 --> 00:15:41.860 Keith: Hey, guys, this is Keith in 363 00:15:41.860 --> 00:15:44.500 Vancouver, Washington, usa, 364 00:15:45.390 --> 00:15:48.350 and I'm just curious about interstellar space 365 00:15:48.430 --> 00:15:51.390 travel. How long do you think it's going to 366 00:15:51.390 --> 00:15:54.270 take for a human to be able to reach 367 00:15:54.670 --> 00:15:57.390 another star? It 368 00:15:57.390 --> 00:16:00.350 seems fairly restrictive with 369 00:16:00.350 --> 00:16:02.350 the distances involved and 370 00:16:03.550 --> 00:16:05.390 you know, what kind of travel 371 00:16:06.590 --> 00:16:08.910 it would take, be it 372 00:16:11.160 --> 00:16:12.680 warp drive or 373 00:16:15.800 --> 00:16:18.440 laser sail. But any, uh, just 374 00:16:18.440 --> 00:16:21.240 curious what you guys think, how long it's 375 00:16:21.240 --> 00:16:23.640 going to take for us to get there and how 376 00:16:23.640 --> 00:16:25.760 realistic it's actually going to be if 377 00:16:25.760 --> 00:16:27.640 anything will ever come of it. 378 00:16:28.600 --> 00:16:30.360 Thanks, guys. Love the podcast. 379 00:16:31.240 --> 00:16:32.840 Andrew Dunkley: Thank you, Keith. Great to hear from you. 380 00:16:33.000 --> 00:16:35.440 There's another place that's not where we 381 00:16:35.440 --> 00:16:38.280 would normally think it was. Vancouver. Like 382 00:16:38.280 --> 00:16:40.600 you automatically go, oh, that's Canada. But 383 00:16:40.600 --> 00:16:42.600 no, he's in the U.S. version. 384 00:16:43.590 --> 00:16:46.360 Uh, yes, uh, but Keith, uh, that's a great 385 00:16:46.360 --> 00:16:48.920 question. Um, I suspect it'll be a 386 00:16:48.920 --> 00:16:51.720 spaceship before it is a human being 387 00:16:51.960 --> 00:16:54.800 going to another star system, or another 388 00:16:54.800 --> 00:16:57.200 star for that matter. Uh, the nearest one's 389 00:16:57.200 --> 00:16:59.480 what, Proxima Centauri, which is 390 00:16:59.560 --> 00:17:02.360 4.41 light years away. So, 391 00:17:03.190 --> 00:17:05.800 uh, using conventional engines, you're 392 00:17:05.800 --> 00:17:08.349 looking at a trip of over 6,000 393 00:17:08.509 --> 00:17:08.909 years. 394 00:17:09.229 --> 00:17:10.075 Professor Fred Watson: 60. 395 00:17:10.263 --> 00:17:12.589 Andrew Dunkley: 60,000 years. Yeah, yeah, yeah. 396 00:17:12.909 --> 00:17:14.829 Okay, well, you know, don't forget to take 397 00:17:14.829 --> 00:17:16.909 some eggs, uh, because 398 00:17:19.069 --> 00:17:21.549 they don't keep that long actually. But no, 399 00:17:21.549 --> 00:17:24.469 they don't. It's, 400 00:17:24.469 --> 00:17:26.669 it's a, ah, it's a difficult one and it sort 401 00:17:26.669 --> 00:17:28.149 of goes back to what we were saying in the 402 00:17:28.149 --> 00:17:30.669 previous episode with Elon Musk and, you 403 00:17:30.669 --> 00:17:32.549 know, getting, um, you know, shooting around 404 00:17:32.549 --> 00:17:35.469 all over the solar system, uh, or 405 00:17:35.469 --> 00:17:38.410 all over the galaxy in the. In, um. 406 00:17:38.410 --> 00:17:38.530 Professor Fred Watson: Um. 407 00:17:38.530 --> 00:17:41.450 Andrew Dunkley: It's. It's not probably a high priority 408 00:17:41.770 --> 00:17:44.770 at this stage and I, I think the day will 409 00:17:44.770 --> 00:17:47.450 come where we'll be able to go faster. 410 00:17:47.450 --> 00:17:50.370 But whether or not we can go fast enough to 411 00:17:50.370 --> 00:17:52.970 make a trip to Proxima Centauri, 412 00:17:53.750 --> 00:17:56.010 um, you know, reasonably quick, 413 00:17:56.990 --> 00:17:59.290 uh, like at 99% 414 00:17:59.450 --> 00:18:02.250 relativistic speed, it would 415 00:18:02.250 --> 00:18:03.290 still take you 416 00:18:05.140 --> 00:18:06.500 about three years, I think. 417 00:18:07.670 --> 00:18:10.380 Professor Fred Watson: Uh, well, it would. No, it must be more than 418 00:18:10.380 --> 00:18:10.780 that because. 419 00:18:10.780 --> 00:18:13.580 Andrew Dunkley: No, well, I'm talking. It'd take you 420 00:18:13.580 --> 00:18:15.700 five. I worked it out, actually. 421 00:18:16.980 --> 00:18:19.940 Professor Fred Watson: It would be. Yeah, at light speed, it takes 422 00:18:19.940 --> 00:18:22.180 you 4.3. 4.4 years. 423 00:18:22.420 --> 00:18:22.980 Andrew Dunkley: Yes. 424 00:18:23.070 --> 00:18:26.020 Professor Fred Watson: Uh, and it. But you're right, you've got to 425 00:18:26.020 --> 00:18:26.140 take 426 00:18:26.140 --> 00:18:27.540 Andrew Dunkley: into account time dilation. 427 00:18:28.100 --> 00:18:30.500 Professor Fred Watson: You do. You've got all of that thrown in as 428 00:18:30.500 --> 00:18:30.820 well. 429 00:18:31.140 --> 00:18:31.620 Professor Fred Watson: Yeah. 430 00:18:31.750 --> 00:18:34.120 Professor Fred Watson: Um, and, uh, it's. 431 00:18:34.750 --> 00:18:37.470 Yes, it's hard to envisage, 432 00:18:37.890 --> 00:18:40.750 um, I mentioned in our, uh, last episode 433 00:18:40.750 --> 00:18:42.670 something about some work I'd seen that 434 00:18:42.670 --> 00:18:44.350 suggested that light sails weren't going to 435 00:18:44.350 --> 00:18:46.830 be the answer for this. Because when you get 436 00:18:46.830 --> 00:18:49.390 to high enough speeds, you get this drag, 437 00:18:49.970 --> 00:18:52.750 uh, that actually slows you down and you've 438 00:18:52.750 --> 00:18:55.350 just got to put so much energy into your 439 00:18:55.350 --> 00:18:58.110 laser pointing at the light sails, 440 00:18:58.550 --> 00:19:00.750 uh, that, um, it really 441 00:19:02.030 --> 00:19:04.830 is probably not going to work very well. 442 00:19:07.150 --> 00:19:09.630 Perhaps the nearest we've got to 443 00:19:09.630 --> 00:19:12.270 seriously thinking about interstellar travel 444 00:19:12.910 --> 00:19:15.470 has been the. What was it? Breakthrough 445 00:19:16.430 --> 00:19:18.670 Starshot. Starshot, that's the one. 446 00:19:19.150 --> 00:19:21.750 That project, which was a 447 00:19:21.750 --> 00:19:24.270 feasibility study funded by 448 00:19:24.590 --> 00:19:27.550 a Russian billionaire whose name was on 449 00:19:27.550 --> 00:19:29.070 the tip of my tongue a minute ago, but has 450 00:19:29.070 --> 00:19:31.990 now disappeared, as names tend to do. Milner. 451 00:19:31.990 --> 00:19:33.450 Yuri Milner. That's his name. 452 00:19:33.450 --> 00:19:34.010 Andrew Dunkley: There he is. 453 00:19:34.250 --> 00:19:35.110 Professor Fred Watson: Yeah. Um, 454 00:19:36.710 --> 00:19:39.370 um. Breakthrough Starshot was feasibility 455 00:19:39.450 --> 00:19:42.290 study to see whether we could, within 456 00:19:42.290 --> 00:19:45.290 a kind of human lifetime, and I think they 457 00:19:45.290 --> 00:19:48.130 were thinking of 20 to 30 years, get a 458 00:19:48.130 --> 00:19:50.290 spacecraft to the vicinity of Proxima 459 00:19:50.290 --> 00:19:52.570 Centauri, the nearest star. Uh, yeah. 460 00:19:53.210 --> 00:19:55.290 Andrew Dunkley: Now, interestingly, while you were talking, I 461 00:19:55.290 --> 00:19:58.250 asked, uh, ChatGPT to work it out. And for 462 00:19:58.250 --> 00:20:00.400 people on Earth, at 463 00:20:00.400 --> 00:20:03.240 99%, uh, of light 464 00:20:03.240 --> 00:20:05.480 speed travelling from Earth to Proxima 465 00:20:05.480 --> 00:20:08.310 Centauri, it would be a, um, 466 00:20:08.320 --> 00:20:11.200 4.3 year journey to get there. 467 00:20:11.760 --> 00:20:14.320 However, when you take into account 468 00:20:14.640 --> 00:20:16.960 time dilation, which becomes significant, 469 00:20:17.840 --> 00:20:20.560 the people on board would only 470 00:20:20.560 --> 00:20:23.320 age 7 months is what it's 471 00:20:23.320 --> 00:20:26.240 saying. I think they're missing something. 472 00:20:26.980 --> 00:20:29.370 Professor Fred Watson: Yeah. In, uh, that calculation, um, 473 00:20:29.540 --> 00:20:31.700 it's probably not that 474 00:20:32.260 --> 00:20:35.140 far Off. Yeah, it might not be just 475 00:20:35.140 --> 00:20:35.940 thinking about. 476 00:20:37.700 --> 00:20:40.340 Andrew Dunkley: So the Earth perspective is a 4.3 year 477 00:20:40.340 --> 00:20:42.220 journey. The onboard travellers would 478 00:20:42.220 --> 00:20:43.460 experience seven months. 479 00:20:43.460 --> 00:20:45.380 Professor Fred Watson: It's critically dependent on how near the 480 00:20:45.380 --> 00:20:46.660 speed of light you get to. 481 00:20:47.060 --> 00:20:48.580 Andrew Dunkley: This uh, is at 99%. 482 00:20:48.740 --> 00:20:51.590 Professor Fred Watson: Yes. Yeah. Uh, 483 00:20:51.700 --> 00:20:54.150 so, yeah, 484 00:20:55.270 --> 00:20:57.750 it's kind of roughly something like that. I'm 485 00:20:57.750 --> 00:21:00.710 sure. I always used to use an example of 486 00:21:00.730 --> 00:21:03.670 um, going to a star a thousand light years. 487 00:21:04.070 --> 00:21:06.950 Sorry, a star 500 light years away. So you 488 00:21:06.950 --> 00:21:09.870 make a thousand year journey as elapsed 489 00:21:09.870 --> 00:21:12.870 on Earth and turns out that uh, I 490 00:21:12.870 --> 00:21:15.790 think it's 99.99995% of 491 00:21:15.790 --> 00:21:18.670 the speed of light. Uh, which is almost the 492 00:21:18.670 --> 00:21:20.670 speed of light. But the people on board have 493 00:21:20.670 --> 00:21:23.380 only aged 10 years. So you've got. In 10 494 00:21:23.380 --> 00:21:25.100 years you've gone a thousand years into the 495 00:21:25.100 --> 00:21:26.220 future on Earth. 496 00:21:27.100 --> 00:21:28.940 Andrew Dunkley: Um, it's crazy, isn't it? 497 00:21:28.940 --> 00:21:31.580 Professor Fred Watson: It's bizarre. Yeah, but, but the 498 00:21:31.580 --> 00:21:34.580 physics. So I, you know, as I 499 00:21:34.580 --> 00:21:36.740 said in last week's episode, I think to talk 500 00:21:36.740 --> 00:21:39.059 about interstellar travel, certainly for 501 00:21:39.059 --> 00:21:42.020 humans at the moment physics 502 00:21:42.020 --> 00:21:44.500 just says no way, Jose. It's. 503 00:21:44.500 --> 00:21:47.020 Andrew Dunkley: Yeah, my new book says otherwise. 504 00:21:47.020 --> 00:21:49.100 Professor Fred Watson: But of course it does. Yeah, but that's. 505 00:21:49.180 --> 00:21:51.180 You're in the real world of science fiction. 506 00:21:51.500 --> 00:21:51.980 Andrew Dunkley: Yes. 507 00:21:51.980 --> 00:21:54.680 Professor Fred Watson: Rather, rather than the artificial world of 508 00:21:54.680 --> 00:21:55.710 uh, relativity. 509 00:21:56.110 --> 00:21:59.110 Andrew Dunkley: Yeah. And just uh, to put Keith right in the 510 00:21:59.110 --> 00:22:02.030 picture, um, you know, if you want to get 511 00:22:02.030 --> 00:22:04.750 to light speed, we're a little bit behind at 512 00:22:04.750 --> 00:22:07.310 the moment. Uh, the Parker solar probe 513 00:22:07.710 --> 00:22:10.590 has currently uh, got the um, space 514 00:22:10.750 --> 00:22:11.870 speed record of 515 00:22:11.870 --> 00:22:16.470 0.064% 516 00:22:16.470 --> 00:22:19.230 of the speed of light. So we're nowhere 517 00:22:19.230 --> 00:22:21.740 near 1%. We're nowhere near 518 00:22:21.740 --> 00:22:22.740 0.1%. 519 00:22:24.340 --> 00:22:26.460 Professor Fred Watson: Is it 190 kilometres per second? 520 00:22:26.460 --> 00:22:28.900 Andrew Dunkley: I think it is, yes, yes, give or take. 521 00:22:29.000 --> 00:22:31.380 Um, that's as fast as we've ever been, 522 00:22:31.900 --> 00:22:34.740 um, as a species. 523 00:22:35.460 --> 00:22:38.020 But um, the day will come we'll get faster. 524 00:22:38.660 --> 00:22:40.020 If we could achieve 2%, 525 00:22:41.960 --> 00:22:44.100 um, that would make travelling to the outer 526 00:22:44.100 --> 00:22:45.900 solar system so much quicker. 527 00:22:45.900 --> 00:22:46.900 Professor Fred Watson: Yeah, it would, yes. 528 00:22:46.980 --> 00:22:49.020 Andrew Dunkley: It would take, it would drop the travel time 529 00:22:49.020 --> 00:22:49.540 to weeks. 530 00:22:50.190 --> 00:22:51.150 Professor Fred Watson: Yeah, yeah. 531 00:22:51.150 --> 00:22:53.390 Andrew Dunkley: Would be amazing. So, you know, we don't need 532 00:22:53.390 --> 00:22:56.110 the speed of light yet, but 533 00:22:56.830 --> 00:22:59.720 we do need to probably get a bit quicker. But 534 00:22:59.720 --> 00:23:02.350 uh, yeah, it's an impossible dream at the 535 00:23:02.350 --> 00:23:04.190 moment, Keith, I think would be the answer to 536 00:23:04.190 --> 00:23:07.030 your question. But um, we won't 537 00:23:07.030 --> 00:23:09.910 give up. I'm sure humanity will figure 538 00:23:09.910 --> 00:23:12.590 out a way to do it at some stage. 539 00:23:13.680 --> 00:23:15.390 Uh, but right now if we want to go anywhere, 540 00:23:15.390 --> 00:23:17.390 we've probably got to build a spaceship big 541 00:23:17.390 --> 00:23:19.910 enough for multiple generations to Live on. 542 00:23:20.790 --> 00:23:23.470 By the time they get there, they'll go, can 543 00:23:23.470 --> 00:23:25.790 anyone why we were coming here in the first 544 00:23:25.790 --> 00:23:28.430 place? Like, this place is the pits. Why did 545 00:23:28.430 --> 00:23:29.110 we come here? 546 00:23:30.870 --> 00:23:31.590 Professor Fred Watson: Exactly. 547 00:23:32.390 --> 00:23:34.150 Andrew Dunkley: Thank you, Keith. Great to hear from you. 548 00:23:36.550 --> 00:23:38.630 Professor Fred Watson: 0G and I feel fine. 549 00:23:38.630 --> 00:23:41.230 Andrew Dunkley: Space nuts now, final question comes from 550 00:23:41.230 --> 00:23:44.030 Mark. I love this question because of the 551 00:23:44.030 --> 00:23:46.960 first sentence. Am I the only person 552 00:23:47.040 --> 00:23:50.000 to have watched Space 1999 back in 553 00:23:50.000 --> 00:23:52.680 the 70s? No, you're not, Mark. I was a 554 00:23:52.680 --> 00:23:55.040 huge fan. I loved that show. 555 00:23:55.770 --> 00:23:58.640 Um, it, it was, uh, on. 556 00:23:59.120 --> 00:24:01.320 It was a British show, British, uh, science 557 00:24:01.320 --> 00:24:03.240 fiction TV programme that ran for two 558 00:24:03.240 --> 00:24:05.200 seasons, 75 to 77. 559 00:24:06.130 --> 00:24:08.530 Um, I watched it on Australian, uh, 560 00:24:09.080 --> 00:24:11.680 television and uh, it follows 561 00:24:11.760 --> 00:24:14.690 311 inhabitants of Moon Base 562 00:24:14.690 --> 00:24:17.250 Alpha, which is hurtling uncontrollably into 563 00:24:17.250 --> 00:24:19.970 space due to an explosion of nuclear waste 564 00:24:19.970 --> 00:24:21.730 stored on the moon's far side. 565 00:24:22.930 --> 00:24:25.010 And this is what's prompt Mark's question. 566 00:24:26.280 --> 00:24:28.210 Uh, I clearly remember a big nuclear 567 00:24:28.210 --> 00:24:31.010 explosion in that show. And next 568 00:24:31.010 --> 00:24:33.290 thing, the moon and the inhabitants of the 569 00:24:33.290 --> 00:24:36.010 moon of, uh, Moon Base Alpha are sent off on 570 00:24:36.010 --> 00:24:38.490 their merry way into deep space, leaving the 571 00:24:38.490 --> 00:24:41.450 Earth, uh, to wobble on its axis. On the 572 00:24:41.450 --> 00:24:44.250 bright side, I do like to sail, so 573 00:24:44.250 --> 00:24:46.970 I wouldn't have to worry about tides. So, 574 00:24:47.130 --> 00:24:49.370 you know, that's pretty cool. 575 00:24:49.760 --> 00:24:52.410 Um, what are your thoughts? P.S. i have 576 00:24:52.650 --> 00:24:54.370 cracked, uh, the screen on my phone, so this 577 00:24:54.370 --> 00:24:55.690 might not make much sense. 578 00:24:57.690 --> 00:24:59.410 Keep, uh, doing what you're doing. It brings 579 00:24:59.410 --> 00:25:01.570 me smiles. It brings a smile to my face. That 580 00:25:01.570 --> 00:25:04.170 comes from Mark. Um, so, yeah, all right, 581 00:25:04.170 --> 00:25:06.580 whatever reason, uh, but in this case it was 582 00:25:06.900 --> 00:25:09.600 nuclear waste explosion that sent the, uh, 583 00:25:09.600 --> 00:25:12.100 moon careening off into the heavens and 584 00:25:12.260 --> 00:25:14.420 left Earth all on its lonesome. 585 00:25:15.460 --> 00:25:17.900 Cause and effect. Um, what would be the 586 00:25:17.900 --> 00:25:20.700 effect, uh, as 587 00:25:20.700 --> 00:25:22.700 well, beyond the fact that the oceans would 588 00:25:22.700 --> 00:25:25.020 be much calmer and you could sail quite 589 00:25:25.020 --> 00:25:27.220 happily. Or would they? No, 590 00:25:27.860 --> 00:25:29.460 No, I didn't think so. 591 00:25:29.780 --> 00:25:32.580 Professor Fred Watson: No, I think it's the, 592 00:25:32.610 --> 00:25:35.530 um, it's the currents 593 00:25:35.850 --> 00:25:38.490 in the ocean and the atmosphere 594 00:25:38.570 --> 00:25:41.570 itself that really dictate what's 595 00:25:41.570 --> 00:25:44.330 happening to the surface of the ocean. The 596 00:25:44.330 --> 00:25:47.170 tidal phenomenon is just a really low 597 00:25:47.170 --> 00:25:49.970 frequency effect. Two high tides a 598 00:25:49.970 --> 00:25:52.810 day. Um, and yes, it does 599 00:25:52.810 --> 00:25:54.810 mean water's moving around. 600 00:25:55.610 --> 00:25:58.410 But, uh, the main, 601 00:25:58.680 --> 00:26:01.680 um, kind of source of motion in 602 00:26:01.680 --> 00:26:03.360 the oceans, I think, are these currents that 603 00:26:03.360 --> 00:26:06.320 we're concerned about because the atmosphere 604 00:26:06.320 --> 00:26:09.320 is changing. Uh, oceans are warming up 605 00:26:09.480 --> 00:26:11.410 and some of these currents are, uh, 606 00:26:12.200 --> 00:26:15.000 forecast to possibly switch off, like the one 607 00:26:15.000 --> 00:26:17.680 that's closest to my heart, because it's 608 00:26:17.680 --> 00:26:20.440 where I grew up. But, uh, the Gulf Stream 609 00:26:20.440 --> 00:26:22.840 Drift, which is a Current that comes up from 610 00:26:23.560 --> 00:26:26.520 the. Basically the West Indies, uh, 611 00:26:26.520 --> 00:26:29.090 and crosses the Atlantic and keeps Scotland 612 00:26:29.090 --> 00:26:31.380 warmer than it otherwise would be. Uh, 613 00:26:31.880 --> 00:26:34.450 um, and of course, western England as well, 614 00:26:34.450 --> 00:26:37.250 and Ireland too. But it's why you can 615 00:26:37.250 --> 00:26:39.770 find. When you look down the west coast of 616 00:26:39.770 --> 00:26:42.650 Britain, you can find palm trees, uh, growing 617 00:26:42.650 --> 00:26:44.210 in people's gardens because of that 618 00:26:44.450 --> 00:26:44.970 phenomenon. 619 00:26:44.970 --> 00:26:45.570 Andrew Dunkley: Floated over. 620 00:26:46.290 --> 00:26:49.080 Professor Fred Watson: Something like that. Yeah. Um, 621 00:26:49.170 --> 00:26:52.050 whereas without it, uh, we'd feel 622 00:26:52.130 --> 00:26:54.650 very much more severe winters. Or they would 623 00:26:54.650 --> 00:26:56.730 up there, because I'm now Australian, of 624 00:26:56.730 --> 00:26:59.650 course. Yeah. Oka. Um, so 625 00:27:00.850 --> 00:27:03.090 it's not going to do much to calm the ocean. 626 00:27:03.430 --> 00:27:06.210 Uh, it would get rid of the tides. Um, it 627 00:27:06.210 --> 00:27:09.010 might, as uh, Mark alluded 628 00:27:09.010 --> 00:27:11.650 to in his question, make the Earth wobble on 629 00:27:11.650 --> 00:27:14.370 its axis a bit more. But that would be over 630 00:27:14.690 --> 00:27:17.560 timescales of tens of thousands of years. Um, 631 00:27:17.560 --> 00:27:19.490 and we might be able to cope with that. But, 632 00:27:20.050 --> 00:27:22.090 um, of course we'd miss it because the moon 633 00:27:22.090 --> 00:27:24.770 is very romantic. And, um. 634 00:27:25.140 --> 00:27:27.220 Andrew Dunkley: Yeah, it's a good thing to photograph 635 00:27:27.220 --> 00:27:27.740 sometimes. 636 00:27:27.740 --> 00:27:29.660 Professor Fred Watson: It's great. That's right. It's good to have. 637 00:27:29.660 --> 00:27:30.100 Yeah. 638 00:27:30.740 --> 00:27:33.660 Andrew Dunkley: It wouldn't make life impossible for us if 639 00:27:33.660 --> 00:27:33.940 it. 640 00:27:34.100 --> 00:27:36.500 Professor Fred Watson: No, it wouldn't. Um, it would change life, 641 00:27:36.660 --> 00:27:39.500 definitely. But I mean, 642 00:27:39.500 --> 00:27:41.740 especially the accelerations that it would 643 00:27:41.740 --> 00:27:44.180 produce as it rocketed off into space 644 00:27:44.820 --> 00:27:47.100 might certainly upset things here on Earth. 645 00:27:47.100 --> 00:27:49.380 There'd be a gravitational influence on. That 646 00:27:49.380 --> 00:27:50.660 could change the length of the day. 647 00:27:51.160 --> 00:27:52.840 Andrew Dunkley: Yeah, that's a thought. 648 00:27:54.520 --> 00:27:57.120 Well, um, you know, people working harder and 649 00:27:57.120 --> 00:27:58.960 harder. You'd probably want the day to go 650 00:27:58.960 --> 00:27:59.480 longer, 651 00:28:02.440 --> 00:28:04.480 but I don't know. I don't know what would 652 00:28:04.480 --> 00:28:07.400 happen. It could be interesting, though. 653 00:28:07.880 --> 00:28:09.920 Professor Fred Watson: Well, it could, but, um, hopefully it's not 654 00:28:09.920 --> 00:28:10.440 going to happen. 655 00:28:11.160 --> 00:28:13.480 Andrew Dunkley: No. It is moving away from us though, Mark, 656 00:28:13.640 --> 00:28:16.440 and it will. Yeah, it will 657 00:28:17.280 --> 00:28:19.160 reach a certain distance and then that'll be 658 00:28:19.160 --> 00:28:20.800 it. It'll stop. It's not going to keep going 659 00:28:20.800 --> 00:28:21.040 away. 660 00:28:21.040 --> 00:28:21.680 Professor Fred Watson: That's correct. 661 00:28:21.840 --> 00:28:24.800 Andrew Dunkley: Yeah. But, um. But at the moment we're 662 00:28:24.800 --> 00:28:27.760 stuck with it. Um, that big grey rock that 663 00:28:27.760 --> 00:28:30.360 just sort of looms over us and looks 664 00:28:30.360 --> 00:28:33.160 pretty and, um, lights up the night. 665 00:28:33.160 --> 00:28:33.640 Professor Fred Watson: It's great. 666 00:28:33.640 --> 00:28:36.520 Andrew Dunkley: Yes. May soon have a colony on it. Ben's 667 00:28:36.520 --> 00:28:37.440 really thrilled about that. 668 00:28:39.760 --> 00:28:42.180 Professor Fred Watson: I don't mind a permanent presence, but, um, 669 00:28:42.180 --> 00:28:44.570 the idea of, you know, settling on the moon 670 00:28:44.570 --> 00:28:46.120 is, uh. 671 00:28:46.890 --> 00:28:49.210 Andrew Dunkley: That's Elon's goal now he's given up on Mars. 672 00:28:49.610 --> 00:28:52.490 Professor Fred Watson: Well, yeah, no, he's talking about Mars as 673 00:28:52.490 --> 00:28:53.090 well in the. 674 00:28:53.090 --> 00:28:55.570 Andrew Dunkley: Oh, I know. With the latest. That's the 675 00:28:55.570 --> 00:28:58.450 latest he's still got. Yeah. But I think 676 00:28:58.450 --> 00:29:00.250 he's decided we'll Go to the moon first and 677 00:29:00.250 --> 00:29:02.370 we'll see how we go there. Yeah, Bit worried 678 00:29:02.370 --> 00:29:03.970 about flushing toilets, but we'll figure that 679 00:29:03.970 --> 00:29:04.250 out. 680 00:29:07.370 --> 00:29:09.050 Uh, Mark, thank you. That's a great question. 681 00:29:09.050 --> 00:29:11.770 Lots of fun and, yeah, space 1999, 682 00:29:12.770 --> 00:29:14.530 probably one of the shows that really 683 00:29:14.610 --> 00:29:17.330 switched my brain onto science fiction and I 684 00:29:17.330 --> 00:29:20.050 haven't let go of it. Terrific show. 685 00:29:20.830 --> 00:29:23.050 Uh, that brings us to the end. But if you do 686 00:29:23.050 --> 00:29:25.090 have questions or comments for us, please 687 00:29:25.090 --> 00:29:27.010 visit our website because we'd love to hear 688 00:29:27.010 --> 00:29:28.810 from you. Uh, and if you've thought about 689 00:29:28.810 --> 00:29:30.570 sending in a question and just never got 690 00:29:30.570 --> 00:29:32.930 around to it, well, get around to it. 691 00:29:33.010 --> 00:29:35.138 SpaceNutsPodcast.com SpaceNuts 692 00:29:35.362 --> 00:29:38.250 IO are our URLs because 693 00:29:38.250 --> 00:29:40.850 we got a 2 for 1 package and you can just 694 00:29:40.850 --> 00:29:43.170 press the AMA button at the top, which means 695 00:29:43.170 --> 00:29:45.590 ask me anything and send us your audio or 696 00:29:45.590 --> 00:29:47.510 text questions. Don't forget to tell us who 697 00:29:47.510 --> 00:29:49.110 you are and where you're from. We always like 698 00:29:49.110 --> 00:29:50.590 to know. We've got people all over the place, 699 00:29:50.910 --> 00:29:53.350 but more listeners in Iceland than anywhere. 700 00:29:53.350 --> 00:29:54.630 We're number one in Iceland. 701 00:29:54.630 --> 00:29:55.390 Professor Fred Watson: Woohoo. 702 00:29:56.670 --> 00:29:59.510 Andrew Dunkley: It's very exciting. Um, but I think we're 703 00:29:59.510 --> 00:30:02.270 number two in Australia and number something. 704 00:30:02.590 --> 00:30:05.150 Number nine in America or something. 705 00:30:05.390 --> 00:30:08.110 Professor Fred Watson: Yes, Number five in the uk. I noticed number 706 00:30:08.110 --> 00:30:08.830 five in the uk. 707 00:30:09.310 --> 00:30:10.870 Andrew Dunkley: What happened to the other two people, I 708 00:30:10.870 --> 00:30:13.270 wonder? Anyway, um, 709 00:30:13.610 --> 00:30:15.690 Fred Watson, we've reached the end. Thank you 710 00:30:15.690 --> 00:30:16.170 so much. 711 00:30:16.330 --> 00:30:18.570 Professor Fred Watson: Great pleasure, Andrew. Always good fun. 712 00:30:19.690 --> 00:30:21.730 Andrew Dunkley: And, uh, thanks to Huw in the studio, who 713 00:30:21.730 --> 00:30:23.930 couldn't be with us today, which is why we're 714 00:30:23.930 --> 00:30:25.690 number two in Australia instead of number 715 00:30:25.690 --> 00:30:28.530 one. He just never listens. And from me, 716 00:30:28.530 --> 00:30:30.010 Andrew Dunkley, thanks for your company. 717 00:30:30.010 --> 00:30:31.970 We'll see you on the next episode of Space 718 00:30:31.970 --> 00:30:33.370 Nuts. Bye Bye. 719 00:30:34.570 --> 00:30:36.770 You've been listening to the Space Nuts 720 00:30:36.770 --> 00:30:39.650 podcast, available at 721 00:30:39.650 --> 00:30:41.720 Apple, Apple Podcasts, Spotify, 722 00:30:41.960 --> 00:30:44.680 iHeartRadio or your favourite podcast 723 00:30:44.680 --> 00:30:46.400 player. You can also stream on 724 00:30:46.400 --> 00:30:49.400 demand@bytes.comm this has been another 725 00:30:49.400 --> 00:30:51.400 quality podcast production from 726 00:30:51.400 --> 00:30:52.600 bytes.com.